The present invention relates to a fire bolt assembly and, more particularly, to a fire bolt assembly preventing opening of a door when exposed to a fire.
It is known to mount a fire bolt assembly in a door for automatically locking the door in a closed state when a fire occurs, preventing flowing of smoke and fire from one side of the door into the other side to increase the time and opportunities of escape. In an approach, a fire bolt assembly includes a receiving tube mounted in a door, a positioning bolt received in the receiving tube and biased by a spring received in the receiving tube, and a stop member secured in an opening of the receiving tube for maintaining the positioning bolt in the receiving tube. The positioning bolt is moved out of the receiving tube and engages with an engaging hole in another door or a door frame when the stop member melts due to the heat of the fire, allowing locking of the door in the event of a fire. However, the spring could lose its elasticity during the fire and, thus, can not reliably push the positioning bolt to the locking position.
Thus, a need exists for a fire bolt assembly for a door which is capable of reliably preventing the door from being opened when exposed to a fire.